The research, published in the Journal of Happiness Studies, suggests that your feelings of happiness and personal well-being rapidly increase as soon as you take that break from the rat race. Then, your relaxation and positive vibes peak on day eight of your getaway, maximizing your feelings of contentment. After that, your enjoyment slowly fades away until day 11, where you’re likely to experience a severe drop-off—maybe due to a bit of homesickness or even boredom. Why day eight? They think that’s how long it takes someone on average to forget and let go of all of their work responsibilities and stress.

Unfortunately, the study also suggests that how long you’re away doesn’t have a huge affect on your happiness after the fun is over. Whether you’re gone for at least eight days or not, those happy-go-lucky effects will likely fade away after just one day of being back at work. You might still feel refreshed, of course, but your mind is quick to snap back to reality when it realizes vacation mode is over.

Still, the researchers suggest it’s a good idea to book a vacation somewhere in the range of seven to 11 days. And try to make day eight the most relaxing of all to reap the maximum benefits. Furthermore, the researchers recommend you take multiple, evenly-spaced vacations of this length a year, as opposed to using all of your vacation time at once. The more opportunity you can give yourself to recharge the better.